Widespread cryptic viral infections in lotic biofilms

Area of Science:

• Microbial Ecology
• Aquatic Virology
• Freshwater Science

Background:

• Viruses significantly impact aquatic microbial ecology, with extensive research in marine environments.
• The role of bacteriophages in freshwater lotic ecosystems, especially benthic biofilms, remains under-investigated.

Purpose of the Study:

• To confirm viruses as consistent members of freshwater stream benthic biofilm communities.
• To ascertain the presence and activity of temperate phages within these biofilms.
• To evaluate the adaptability of community profiling methods, such as random amplified polymorphic DNA-PCR (RAPD-PCR), for characterizing biofilm viral communities.

Main Methods:

• Field and laboratory experiments were conducted to assess viral presence and activity.
• Prophage induction assays were performed to detect temperate phage activity.
• Random amplified polymorphic DNA-PCR (RAPD-PCR) was employed for viral community profiling.

Main Results:

• Results indicate that viruses are consistently present in lotic biofilm communities.
• Prophage induction was statistically significant, though a small fraction of bacteria harbored or induced prophages.
• RAPD-PCR suggested temporal shifts in viral communities correlated with biofilm maturity.

Conclusions:

• Viruses are integral components of freshwater stream benthic biofilms.
• Temperate phage activity is present but limited within these communities.
• RAPD-PCR shows promise for profiling viral communities, but requires further development for quantitative applications.